After years of research on dolphin behavior and under pressure from animal rights groups, the National Aquarium in Baltimore has decided to move the marine mammals to a sanctuary, officials said Wednesday.

Reports last week of serious under-reporting of fish catches in New Zealand fisheries and lack of prosecution of alleged perpetrators is mirrored in reporting of marine mammals bycatch, say University of Otago marine mammal ...

Scientists have known for decades that modern-day dolphins are some of the most intelligent and social animals on earth. Demonstrating complex behaviour and communication dolphins remind us of ourselves while living in a ...

In a new study, most marine mammals were found to exhale carbon monoxide at levels equivalent to or greater than the amount exhaled by a several-packs-a-day smoker. The research led by researchers at Scripps Institution of ...

New research finds there is a distinct sound coming from a massive community of fish, shrimp, jellies and squid as they travel up and down from the depths of the ocean to the water's surface to feed. This sound could be serving ...

School of Medicine researchers working with the U.S. Navy's Marine Mammal Program in San Diego have discovered a startling variety of newly-recognized bacteria living inside the trained dolphins that the Navy uses to find ...

Marine mammal

Marine mammals are a diverse group of roughly 120 species of mammal that are primarily ocean-dwelling or depend on the ocean for food. They include the cetaceans (whales, dolphins, and porpoises), the sirenians (manatees and dugong), the pinnipeds (true seals, eared seals and walrus), and several otters (the sea otter and marine otter). The polar bear, while not aquatic, is also usually considered a marine mammal because it lives on sea ice for most or all of the year.

Marine mammals evolved from land dwelling ancestors and share several adaptive features for life at sea such as generally large size, hydrodynamic body shapes, modified appendages and various thermoregulatory adaptations. Different species are, however, adapted to marine life to varying degrees. The most fully adapted are the cetaceans and the sirenians, which cannot live on land.

Despite the fact that marine mammals are highly recognizable charismatic megafauna, many populations are vulnerable or endangered due to a history of commercial exploitation for blubber, meat, ivory and fur. Most species are currently protected from commercial exploitation.